<!DOCTYPE html>
<body onload="f()">
  <p>First</p>
  <p>Second</p>
  <p>Third</p>
  <script>
    function f() {
      var p = document.getElementsByTagName("p")[1];
      var style = document.createElement("style");
      style.setAttribute("scoped", "");
      style.textContent = "p { color: green }";
      p.appendChild(style);
    }
  </script>
</body>
